Human skeletal muscle-derived stem/progenitor cells modified with connexin-43 prevent arrhythmia in rat post-infarction hearts and influence gene expression in the myocardium

Stem cell therapy in combination with genetic modification (e.g., transfection with the coding sequence for the connexion 43 gene, GJA1) may solve the problems associated with the occurrence of additional (secondary) stimulation in the post-infarcted heart (arrhythmia). Human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) were transfected with the pCiNeo-GJA1 plasmid at an efficiency of approximately 96%. Gene overexpression was assessed using qPCR, and subsequent analysis revealed that GJA1 expression increased more than 40-fold in SkMDS/PCs transfected with the appropriate coding sequence (SkMDS/PCsCX43) compared to that of the 'native' SkMDS/PCs control (SkMDS/PCsWT). Enhanced (4-fold) protein expression of connexin-43 was also confirmed by Western immunoblotting. Furthermore, using the arrhythmic score, we demonstrated the positive effects of SkMDS/PCsCX43 cell intervention in reducing additional secondary stimulations in rat post-infarcted hearts compared with that of wild-type cell delivery. Selected gene responses (Kcnq1, Cacna1c, Ncx1, Serca2a, and Tgfb1) showed significantly altered expression profiles in the rat myocardium upon intervention with SkMDS/PCsCX43. The genetic modification of human skeletal muscle-derived stem/progenitor cells with connexin-43 prevented the pro-arrhythmic effects of myogenic implanted stem cells on the host myocardium and positively influenced myocardial gene expression profiles in respect to myocardium conductivity.

Influence of hypoxia prevailing in post-infarction heart on proangiogenic gene expression and biological features of human myoblast cells applied as a pro-regenerative therapeutic tool

Cardiovascular diseases along with MI (myocardial infarction) lead to regional ischaemia and hypoxic conditions, which prevail after infarction. Diminished O₂ saturation which is related to elevated level of hypoxia inducible factor 1 (HIF-1) transcription factor, may switch the expression of many genes. To maximize effect of therapies proposed by regenerative medicine, it is essential to verify (within different time points after MI) the expression of proangiogenic genes and their receptors that are regulated, along with the expression of HIF-1α. We demonstrated a connection between the expression of Hif-1α (in murine post infarcted heart model) and the proangiogenic genes Vegf-a; and Plgf and their receptors during myocardial hypoxia. The innovative part of the study required establishment of the most accurate in vitro O₂ level corresponding to the hypoxia level prevailing in myocardium after MI. We determined the influence of hypoxia on the biology of human myoblasts in in vitro oxygen conditions (3%), corresponding to those prevailing in the heart after an infarction using a murine model. We also tested myoblasts that were genetically modified with VEGF-A/FGF-4 and PlGF under hypoxic conditions and compared their characteristics with cells cultured under normoxia and hyperoxia (standard in vitro conditions) with respect to myogenic gene expression, cell proliferation, fusion potential and proangiogenic function. The examination of genetically modified myoblasts under optimized in vitro hypoxia conditions led to the conclusion that hypoxia did not negatively influence the biological functions of the myoblasts, such as cell proliferation and/or proangiogenic characteristics. These results support the expected increased proregenerative effects of such genetically modified human myoblasts.

Sperm mitochondrial dysfunction and oxidative stress as possible reasons for isolated asthenozoospermia

Reduced sperm motility, defined as asthenozoospermia, is a frequent cause of male infertility, and is mainly connected with the dysfunction of sperm mitochondria. The aim of this study was to identify the proteins, and thereby the metabolic pathways, responsible for asthenozoospermia, using 2-DE and MALDI-TOF MS, and correlate the results obtained with those of two mitochondrial tests: JC-1 and MitoSox Red. The JC-1 test was performed to test sperm mitochondrial activity, and the MitoSox Red test was performed to check whether the observed sperm poor motility is associated with mitochondrial reactive oxygen species (ROS) production. To identify proteins strictly connected with reduced sperm motility, men with isolated asthenozoospermia (n = 4 versus 10 normozoospermic controls) alone were included in the study. The proteomic analyses resulted in the identification of 25 sperm proteins that are differentially expressed in asthenozoospermic individuals. Most of the identified proteins were downregulated and were involved in energy production; however, we have also identified structural sperm proteins and proteins secreted by the epididymis. The latter, together with the results from MitoSox Red assay, may provide insights into the pathophysiological basis of asthenozoospermia.

Implantation of autologous muscle-derived stem cells in treatment of fecal incontinence: results of an experimental pilot study

Background

The aim of this study is to present results of the implantation of autologous myoblasts into the external anal sphincter (EAS) in ten patients with fecal incontinence.

Methods

After anatomical and functional assessment of the patients’ EAS, a vastus lateralis muscle open biopsy was performed. Stem cells were extracted from the biopsy specimens and cultured in vitro. Cell suspensions were then administered to the EAS. Patients were scheduled for follow-up visits in 6-week intervals. Total follow-up was 12 months.

Results

All biopsy and cell implantation procedures were performed without complications. Nine of the patients completed a full 12-month follow-up. There was subjective improvement in six patients (66.7 %). In manometric examinations 18 weeks after implantation, squeeze anal pressures and high-pressure zone length increased in all patients, with particularly significant sphincter function recovery in five patients (55.6 %). Electromyographic (EMG) examination showed an increase in signal amplitude in all patients, detecting elevated numbers of propagating action potentials. Twelve months after implantation two patients experienced deterioration of continence, which was also reflected in the deterioration of manometric and EMG parameters. The remaining four patients (44.4 %) still described their continence as better than before implantation and retained satisfactory functional examination parameters.

Conclusions

Implantation of autologous myoblasts gives good short-term results not only in a subjective assessment, but also in objective functional tests. It seems that this promising technology can improve the quality of life of patients with fecal incontinence, but further study is required to achieve better and more persistent results.